High voltage nonarcing selector switch



L. C. STRINGER HIGH VOLTAGE NONARCING SELECTOR SWITCH June 20, 1939.

Filed April 29, 1937 I j V v7////// 7/////////6///////////// Inventor Aitorneys Patented June 20, 1939 UNITED STATES PATENT OFFICE Louis C.Stringer, Chicago, 111., assignor to Electronics Supply Corp., acorporation of Delaware Application April 29, 1937, Serial No. 139,822

lClllm.

The invention herein shown, described and claimed, pertains to astructurally novel and improved rotary, manually controlled, highvoltage selector switch expressly designed to abolish with 5 certaintythe ever objectionable dragging of an arc not now satisfactorilyovercome by present prevailing selector switches.

Needless to say, I am generally conversant with the prior state of theart to which the in- 10 vention-relates, as well as the industrialconditions prevailing. As a matter of fact, it is common knowledge amongthose skilled in the line of endeavor with which we are here concernedthat where electrical energy is stepped up to a l5 potential orfrequency susceptible of developing an arc, as in step-up transformationwhere an appreciable intensitive current is involved, the user of theordinary selector switch is confronted with the problem known asdragging an arc,

20 with the attendant result of burning and damaging not only theselector arm, but the contact point as well.

Although efforts have been made by my predecessors striving to cope withthis undesirable 25 state of affairs, in so far as I have been able toascertain structures provided therefor are incapable of satisfactorilyaccomplishing results in keeping with the demands of the trade. Itfollows, therefore, that my objective, in the main, is

80 to generally improve upon prior patented and marketed switchconstructions through the adoption and use of a switch or equivalentstructure which may be successfully used ofi a connection of the highside of a transformer without the 85 attendant disadvantages and damagespresent in available constructions.

In reducing to practice the principles of the broad inventive conceptwith which we are herein concerned, I have evolved and produced a sim-40 ple, fool-proof, and aptly fitted structural assemblage calculated tocorrect existing conditions, this being attained through theinstrumentality of means incorporated in the switch whereby before theselector arm can be conveniently released and set into motion, thesource of current may be temporarily out off rendering the switch deaduntil the selector arm has been completely adjusted from a given contactto a predetermined selected contact.

Features and advantages supplementary to those so far exposed willbecome more readily apparent from the following detailing descriptionand accompanying drawing.

55 In the drawing, wherein corresponding numerals are employed todesignate like parts throughout the views:

Figure 1 is a view, partly in section, and partly in elevation,illustrating the preferred embodiment of the invention possessing themerits hereinafter defined and claimed.

Figure 2 is a horizontal section on the plane of the line 2-2 of Figure1.

Figure 3 is a horizontal section of a fragmentary character on the line33 of Figure 1, looking in the direction of the arrows.

Figure 4 is a fragmentary elevational view of the make and break devicein the source of electrical supply.

Reference being had now to the drawing by distinguishing referencenumerals, it will be observed that the numerals 5 and 6 designate spacedparallel plates of appropriate insulation material. These are joined inparallelism by connecting bolts 1 surrounded by spacing sleeves 2o 8interposed between the parts as portrayed to advantage in Figure 1. Onthe disc 5, preferably the margin thereof, and at circumferentiallyspaced equi-distant points, are the contact buttons 9 with the powertake-01f binding posts I0.

The numeral H designates a rotary tubular actuating handle mounted forrotation in the upper plate or disc 5 and held partially in place by theretention ring l2. On the upper end of the handle is an appropriatecontrol knob I3 suitably knurled. On the interior and adjacent the upperend is a fitting or insert 14 constituting an abutment or shoulder. Onthat portion of the handle .forming the lower end and located betweenthe discs 5 and 6 is a collar fixedly attached to the handle. Thiscollar I5 carries the integral lateral selector finger or arm I5. Aneccentric socket is formed in the collar parallel to the handle toaccommodate a spring-pressed detent l1 accessible by way of the plug nutl8. The pointed end of the detent is cooperable with keeper notches orseats l9 formed in the under side of the companion keeper ring 20.Electrically connected with the lateral extension on the margin of thering 20 is a binding post 2i delivering the transformed or controlledcurrent to the selector switch. In actual practice the keeper seats IQfor the latch or detent I! are precisely milled to be in coincidentalradial alignment with the peripheral stationary contact buttons orelements 9. Consequently, each keeper notch registers with itsassociated contact, making it possible to mechanically lock the contact56 finger or arm l6 against accidental displacement when once it isadjusted to place.

I next call attention 'to a reciprocatory or slidably mounted rod22.slidably mounted in the tubular handle H and operable through thecollar M. It is provided on its upper end with a concentric secondaryknob 23 coordinated with the main'control knobylii. A coil spring 24 isinterposedbetween the collar M and the knob 23 to maintain the latterprojected to the position illustrated in the drawing. The rod or member22 is the control means for the circuit make and break device denoted bythe numeral 25.

movable contact 21, with which the current supply wires 28 and 29connect. The wires 28" and 29 are maintained normally in electricalcircuit by the contacts 26 and 21, these being maintained in circuitmaking condition by the spring 24.

In practice it is obvious that the discs 5 and 6, the handle II, theknob l3, the rod 22, and knob 23, the collar l4 are of insulationmaterial. The keeper ring 20, the collar. I5, the finger I6, andcontacts, are of course of electricity conducting material.

The operation of the'switch is as follows: Upon placing the hand of theoperator on the previously described wheel or knob l3, a movement of thecontact finger I 6 cannot take place until sufficient pressure from thepalm of the hand is exerted to acquire the desired oscillatory or rotarymotion. The pressure is simultaneously brought to bear on the auxiliaryknob 23, driving the rod 22 downwardly, disengaging the contact 21, andopening the power circuit at the breaking point 25. Thus, by cutting offthe supply of current momentarily, the whole selector switch is rendereddead for corresponding periods, allowing the arm IE to be shifted fromone contact to another at the discretion of the user. therefore, thatduring this shift, the aforementioned objectionable dragging of an arcis positively eliminated.

It is thought that the description taken in connection with the drawingwill enable a clear understanding of the invention to be had.

.This comprises relatively stationary contact 26 and It follows,

Therefore, a more lengthy description is thought unnecessary.

While the preferred embodiment of the invention has been shown anddescribed, it is to be understood that minor changes coming within thefield of invention claimed may be resorted to if desired. 3'

A selector switch of thejclass described comprising a pair of spacedparallel plates of insulation material, a plurality-of circumferentiallyspaced contact buttons'mounted on the under side of the top plate, saidcontact buttons including individual binding poststo accommodate powertake-off wires, a metallic ring secured to the central portion of theunder side of said top plate,

said top plate having an opening in alignment with the opening of saidring, said ring being provided on its under side with radial keepernotches, a tubular handle mounted for rotation in the apertured portionof said top plate and extending through and beyondsaid ringandterminatingshort of .the bottom plate, a collar secured to the lower endof said handle, said tact member cooperable with said first namedmember, a. second conductor wire connected with said movable contactmember, a rod slidably mounted in said bottom plate, said movablecontact member being mounted on'said rod, said rod extending upwardlythrough the tubular handle,

said handleand said rod being provided with closely allied operatingknobs, a stop shoulder mounted in said handle, a coiled spring on saidrod engageable .with said stop shoulder and the adjacent knob whereby tomaintain the movable contact member in normal electrical connection withthe stationary member.

LOUIS C. STRINGER.

